Multiple switch for electronic musical instruments

ABSTRACT

A multiple switch for an electronic musical instrument comprising a multipolar magnet which has a plurality of magnetic poles arranged alternately opposite to each other, and plural pieces of magnetosensitive elements whose electric resistance varies according to the direction and the intensity of applied magnetic field, wherein each of said magnetosensitive elements is arranged between a pair of said magnetic poles of said multipolar magnet and connected in the switching circuit of the electronic musical instrument, and the relative positions of said magnetic poles and said magnetosensitive elements are caused to change by one step under the action of the corresponding key, so that the electrical resistance of the magnetosensitive elements is varied and switching on-off actions are attained.

United States Patent inventor Appl. No.

Filed Patented Assignee Priority MULTIPLE SWITCH FOR ELECTRONIC MUSICAL Junji Olino Hamamatsu-shi, Japan 837,540

June 30, 1969 Jan. 4, 1972 Nippon Gakki Seizo Kabushiki Kaisha Shi zuoka-ken, Japan July 5, 1968 Japan INSTRUMENTS 4 Claims, 5 Drawing Figs.

Int. CL...

Primary Examiner-Rodney D. Bennett, Jr. Assistant Examiner-Rv Kinberg Attorney-Wenderoth, Lind & Ponack ABSTRACT: A multiple switch for an electronic musical instrument comprising a multipolar magnet which has a plurality of magnetic poles arranged alternately opposite to each other, and plural pieces of magnetosensitive elements whose electric resistance varies according to the direction and the intensity of applied magnetic field, wherein each of said magnetosensitive elements is arranged between a pair of said magnetic poles of said multipolar magnet and connected in the switching circuit of the electronic musical instrument, and the relative positions of said magnetic poles and said magnetosensitive elements are caused to change by one step under the action of the corresponding key, so that the electrical resistance of the magnetosensitive elements is varied and switching onoff actions are attained.

PATENIED JAN 4:972

SHEET 1 OF 2 Fig. 3

Fig.2

INVENTOR. J u nj i O H N O BYMMIZLQZJIL PATENIEUJAN 41972 SHEEI 2 BF 2 This invention relates to a. multiple switch for electronic musical instrumentsusingplural pieces of magnetosensitive elements whose electric resistance varies according to the direction and the intensity of applied magnetic field.

Electronic musical instruments are usually provided with tone generators and switches which control the outputs of said tone generators. Accordingly, many electric contacts are always necessary for electronic musical instruments, and as the electric contacts, metal-to-metal contacts or metal-to-conductive-rubber contacts are used. But, these are liable to cause miscontacts owing to the formation of sulfides or oxides of metals or deposits of dust on the surface of the contacts, therefore they are unreliable and liable to produce noises.

A principal object of the present invention is to provide a multiple switch for electronic musicalinstrurnents which does not produce noises and also able to provide a large control ratio minimizing a sound leakage without using any electric contact in switching the output of a tone generator.

According to thepresent invention, a multiple switch for an electronic musical instrument is composed of a multipolar magnet of a plurality of alternately reversed polar magnets and plural pieces of magnetosensitive elements whose electric resistances vary according to the directions and the intensities of applied magnetic fields, wherein said magnetosensitive elements are arranged between the magnetic poles ofgsaid multipolar magnet andthe relative placement of said'magnetic poles and said magnetosensitive elements is shifted by one step under the action of the corresponding key, the electrical resistance of said magnetosensitive elements being varied thereby, and said magnetosensitive elements are connected in the switching circuit of the electronic musical instruments.

These and other objects and features of this invention will be better understood upon consideration of the following detailed description andthe accompanying drawings in which:

FIG. 1 is a side view of a keyboard of an electronic musical instrument fitted with a multiple switch of an embodiment according to the invention;

F IG.'2 is an enlarged perspective view of said switch;

FIG. 3 is a perspective view of the switch of the another embodiment according to the invention;

FIG. 4 is a side view, partly in section, of the switch of still another embodiment according to the invention; and

FIG. is a front view of the switch shown in FIG. 4.

With reference now to the drawing and more particularly to FIG. 1 thereof, there is illustrated a keyboard of an electric musical instrument according to the present invention, in which the numeral 1 is a key, 2 is a keyboard frame holding said key, and mounted on these elements is a switch according to the present invention. The switch consists of a multipolar magnet 3' and plural pieces of magnetosensitive elements 7, 7' and 7", and said multipolar magnet 3 is fixed to a magnet holder 3 so as to be driven by the depression of the key 1, and said magnetosensitive elements are fixed to a downward extended support 8 under said keyboard frame 2. The magnet holder 3 is fixed to a spring holder 4 through plate or leaf spring 4 so as to be movable vertically through the actuation of the key 1, and said spring holder 4 is fixed to the keyboard frame 1. The multiple magnet 3' comprises north poles 5,5, 5 and 5", and south poles 5, 6' and 6" arranged alternately, as shown in FIG. 2, and thus alternately reversed magnetic fields are provided with between said magnetic poles. These magnetic poles are arranged vertically at regular intervals which correspond to the displacement of each magnetic poles by the maximum movement of the key 1. Accordingly, when the key 1 is pushed down to the maximum extent, the north poles 5, 5' and 5" come down respectively to the positions of the south poles 6, 6 and 6", and the south poles 6 6' and 6 come down respectively to the positions of the north poles 5, 5" and 5". The magnetosensitive elements 7, 7' and 7" are fixed to the downward extended support 8 and arranged respectively at the positions between south pole 6 and north pole 5, south pole 6' andnorth pole 5", and southpole 6" and north pole 5". These elements .are connected in the switching circuit of the electronic musicalinstrument through lead wires 9. I 1 i i The magnetosensitiveelements 7, 7'- and 7" may be of such a type as permits electric current to flow while the key 1 is undepressed or of such a type aspermits electriccurrent not to flow while the key is undepressed when the key 1 is pushed down, the magnetic poles 5, 5 5.";and 6, ,6" and 6" displace by one step, accordingly the direction of the magnetic fields applied to the magnetosensitive elements 7, 7' and 7 are reversed and the magnetosensitive elementsare altered either from conductive; to nonconductive state or from nonconductive to conductive state. Thus, the magnetosensitive elements connected in the switching circuit serve for switching the outputof atone generator, tone signals being taken out when the key is depressed and not when the key is undepressed.

Another example is shown in FIG. 3, inwhicha pair of north pole 10 and south pole 11 arearranged in horizontally spaced relationship, below them thesecond pair ofnorth pole l0 and south pole 11., the third pair of north pole l0" and south pole 11", and the fourth pair; of north pole. 10" and south pole 11" are arranged with their polarities being reversed alternately, and thus alternately reversed magnetic fields are generated. The magnetosensitive elements 12, 12 and 12" are arranged respectively between the poles 10' and 11, 10" and 11", and 10" and 11". This switch functions in the same way as the switch of example 1.

FIGS. 4 and 5 show still another switch of the embodiment according to the present 'nvention, wherein a pair of magnetic poles of the same type as that shown in. FIG. 2, are arranged circularly around the central axis. In the figure, 13 is a diskshaped magnet holder, a pair of said magnet holders facing each other in spacedrelationship, 14 is the central axis of said holder and 18 is connecting rod coupled, to the key not shown to rotate said magnet holder. The rr agnet holder 13 is provided with a multipolar magnet, or a plurality of magnets with north andsouth magnetic poles 15 an d 16 being arrangedalternately, similarly asshownin FIG. 2, to provide alternately opposite magnetic fields, and the magnetosensitive elements l7, l7 are arranged respectively at the position between said north poles 15 15 and south poles l6, l6 The magnetosensitive elements are, for example, made not to permit eiectric current to flow when the key is not pushed down. And the positions of the magnetic poles l5, and 16, 16 are made to displace by one step inaccordance with the rotation of the magnet holder 13 around the axis 14 driven by the connecting rod 18,,c0rresponding to the depression of the key. Accordingly, the direction of magnetic fields applied to the magnetosensitive elements 17, 17 is reversed and said magnetosensitive elements become conductive and thus a sound circuit comes into operation. This embodiment is suitable for use in tablet switches as stop tablets in an electronic musical instrument.

As above described, the switch of this invention is very effective practically, producing no noise, because of the magnetic switching by the magnetosensitive elements without using any conventional electric contact as the switch for the electronic musical instruments. Moreover, according to the present invention, a large control ratio is obtained with lesssound leakage, because the magnetic field applied to the magnetosensitive elements is reversed by the action of the key owing to the alternately reversed arrangements of the magnet poles.

In general, each element of the multiple switch must be provided with two pairs of magnetic poles for switching on or off, however, according to the present invention, it is to be provided with only one additional pair of magnetic poles more than the number of the elements of the switch, utilizing the adjacent reversed magnetic field in the multiple magnet, and thus it is possible to be installed compactly in a small space under the keyboard.

It is intended, therefore, that all matter contained in the foregoing description and in the drawings shall be interpreted as illustrative only not as limitative of the invention.

What is claimed is:

l. A multiple switch for an electronic musical instrument comprising a key, a magnet holder actuated by said key, a multipolar magnet composed of plural pieces of north and south magnetic poles arranged in alternately opposite polarities, said magnet being fixed to said magnet holder, and magnetosensitive elements arranged between each pair of said plural pieces of north and south magnetic poles and connected in the switching circuit of the electronic musical instrument as switch element, the electric resistance of said magnetosensitive elements being varied in accordance with the direction and intensity of the magnetic field applied thereto, whereby the relative position of said magnetic poles and said magnetosensitive elements are caused to change by one step under the action of the key and the electric resistance of said magnetosensitive elements is varied. v

2. A multiple switch for an electronic musical instrument according to claim 1, wherein said plural pieces of north and south magnetic poles are arranged vertically.

3. A multiple switch for an electronic musical instrument according to claim 1, wherein said north and south magnetic poles are arranged in horizontally spaced relationship to each other.

4. A multiple switch for an electronic musical instrument according to claim 1, wherein said plural pieces of north and south magnetic poles are arranged circularly around a diskshaped magnet holder. 

1. A multiple switch for an electronic musical instrument comprising a key, a magnet holder actuated by said key, a multipolar magnet composed of plural pieces of north and south magnetic poles arranged in alternately opposite polarities, said magnet being fixed to said magnet holder, and magnetosensitive elements arranged between each pair of said plural pieces of north and south magnetic poles and connected in the switching circuit of the electronic musical instrument as switch elements, the electric resistance of said magnetosensitive elements being varied in accordance with the direction and intensity of the magnetic field applied thereto, whereby the relative position of said magnetic poles and said magnetosensitive elements are caused to change by one step under the action of the key and the electric resistance of said magnetosensitive elements is varied.
 2. A multiple switch for an electronic musical instrument according to claim 1, wherein said plural pieces of north and south magnetic poles are arranged vertically.
 3. A multiple switch for an electronic musical instrument according to claim 1, wherein said north and south magnetic poles are arranged in horizontally spaced relationship to each other.
 4. A multiple switch for an electronic musical instrument according to claim 1, wherein said plural pieces of north and south magnetic poles are arranged circularly around a disk-shaped magnet holder. 